Power conversion systems, such as variable-speed, constant-frequency (VSCF) power conversion systems, are commonly used in aircraft and aerospace applications to generate AC and DC power from a prime mover, such as a jet engine. In such an application, variable-frequency AC power may be produced by a brushless, synchronous generator driven by the jet engine. The variable-frequency AC power is converted to DC power by an AC/DC converter, such as a rectifier bridge. An inverter is coupled to the AC/DC converter to transform the DC power into constant-frequency AC power, which is then filtered by a filter. The filtered AC output is then provided to an AC load bus which supplies power to various points throughout the aircraft.
The inverter used in VSCF systems may be of the stepped-waveform type. An inverter of this type is disclosed in U.S. Pat. No. 3,775,662 to Compoly, et al. Such a stepped-waveform inverter generates an output having a stepped shape that generally approximates a sine wave. The purpose of approximating a sine wave is to reduce the size of the filters, provided at the output of the inverter, that are used to remove unwanted harmonics. While previous stepped-waveform inverters may accomplish such goals, efficient and effective methods of control of such inverters have heretofore been lacking.